Floating crane



Jan. 30, 1962 H. ERNST 3,018,901

FLOATING CRANE Filed Sept. 12, 1960 2 Sheets-Sheet 1 Ill INVENTOR Hal/mu! Ernst MI Z TOR E YJ Jan. 30, 1962 H. ERNST 3,018,901

FLOATING CRANE Filed Sept. 12, 1960 2 Sheets-Sheet 2 INVENTOR United States Patent 3,018,901 FLOATING CRANE Hellmut Ernst, Nurnberg, Germany, assignor to Maschinenfabrik Augsburg-Nurnberg A.G., Nurnberg, Germany Filed Sept. 12, 1960, Ser. No. 55,448

Claims priority, application Germany Sept. 22, 1959 3 Claims. (Cl. 212-3) This invention relates to a floating crane having a counterbalancing platform supported by a rotary mast. In particular, the invention is directed to a derrick-type self-slewing crane mounted on a floating vessel, such as a pontoon or barge.

The object of this invention is to construct a floating rotary crane having a very low center of gravity.

This and other objects are obtained by having the juncture between the rotary mast and the vessel formed by means of a post which is firmly united with the mast and which is supported on the vessel by means of a thrust bearing and a flanged ring collar bearing. A juncture between a rotary crane mast and a bearing member is in of itself old in the construction of dock-side cranes, but is new when employed in a floating crane. A dock-side crane is not designed for a low center of gravity, but for occupying as small as possible dock-side area and for good visibility. According to this invention, as compared to other self-slewing floating cranes, the advantage is obtained of a lighter weight crane as the supporting bearing member is now formed as a part of the vessel body. Now, for any given height for the mast, the bearing for the mast can be positioned as low as possible in the hull of the vessel. In other form of this invention, the thrust bearings for the mast can be placed in a well depressed below the keel of the vessel. By so doing, the total center of gravity can be lowered still further.

The center of gravity can be lowered even further by attaching an engine platform to the mast and positioned directly above the deck of the vessel. The bearing portion of the mast together with the platform thus forms an angle-shaped supporting member to which the mast is hingedly joined for carrying a sheave for the hoist rope. Tension on the mast is relieved by struts or stifilegs extending from the top of the mast to the rear end of the platform. By reason of this construction, the upper part of the mast and bearing system is of much lighter weight so that the center of gravity of the crane structure is lowered, and this means that the center of gravity of the entire floating crane, including the vessel, is likewise lowered.

The means by which the objects of the invention are obtained are described more fully with reference to the accompanying drawings, in which:

FIGURE 1 is a front view of a derrick crane with a portion broken away; and

ice

FIGURE 2 is a similar view of a modified form of the invention.

As shown in FIGURE 1, the vessel 1, such as a floating barge or pontoon, carries a mast 2 which is extended into a foot bearing post 3 journalled in a thrust bearing 4 and further supported by a ring flange collar bearing 5 rotatable on top or" the bearing block. Mast 2 can either be solid or hollow and can have a circular or angular cross-sectional shape throughout all or a portion of its length. A lattice-type construction can be used to form a hollow column.

The bearing post 3 extends below the collar bearing 5. A sheave 6 for the hoist rope '7 is carried on the upper end of mast 2. The operators cabin 8 is joined to the lower portion of the mast as is the engine platform 9, the latter being located opposite the boom 10 as a counterbalance. Derrick boom 10 is joined to mast 2 by means of the boom angle ropes 11.

In FIGURE 2, the bearing post 3 carries a transversely extending engine platform 12 to form an angle supporting member for the mast. The thrust bearing for post 3 is positioned in a well 13 extending below the keel of vessel 1. Mast 14 is hinged to platform 12 in alignment with post 3. The upper end of mast 14 carries sheave 15 for the hoist rope 16. Tension struts or stifflegs 17 extend from the top of mast 14 to the rear of platform 12. The engine room 18 is carried on platform 12 and the operators cabin is fastened to mast 14. Boom 2G is counterbalanced by platform 12 and is lifted or lowered by means of boom angle ropes 21.

Having now described the means by which the objects of the invention are obtained,

I claim:

1. In a rotary floating crane having a vertical mast rotatably mounted upon a vessel, a derrick boom attached to said mast, and a boom counterbalancing engine platform extending from the foot of said mast, the improvement comprising a journal post joined to the foot of said mast and extending into a thrust bearing positioned in the interior of said vessel, and a flanged ring bearing secured to said post at the foot of said mast.

2. In a crane as in claim 1, said thrust bearing being positioned in a well extending below the keel of said vessel.

3. In a crane as in claim 2, said engine platform being joined at an angle to the upper end of said post and lying directly above the deck of said vessel, said mast being hingedly secured to said platform, and a tension strut joined to the top of said mast and to said platform.

References Cited in the file of this patent UNITED STATES PATENTS 50l,492 Chilson July 18, 1893 840,684 Bode et al. Jan. 8, 1907 1,147,176 Kimmel July 20, 1915 

